CODEWITHSUNDEEP
opengltransformation
Merni
Merni

Reputation: 2922

Rotation in opengl

I have a plane and I want to rotate it around the y axis. The planes coordinates are in:

Vec4f(-1,-1, -5, 1),
Vec4f( 1,-1, -5, 1),
Vec4f( 1, 1, -5, 1),
Vec4f(-1, 1, -5, 1),

I just want the plane to rotate, not go around in circles, so I translate it back to origin a then do the rotation:

glTranslatef(0,0,-5);
glRotatef(50.0*t, 0, 1, 0);

draw(plane);

But the plane still makes a circle around the origin. What am I doing wrong?

Upvotes: 1

Views: 464

Answers (1)

datenwolf
datenwolf

Reputation: 162317

Transformations apply in the opposite order in which you multiply them, also you might want to translate back to where it came from. So change it like this: 

translation = -5;
if(translate_back) glTranslatef(0,0,-translation);
glRotatef(50.0*t, 0, 1, 0);
glTranslatef(0,0,+translation);

Upvotes: 3

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